docstr: Class-specific build method to be overridden by child classes.
docstr_tok: ["Class-specific","build","method","to","be","overridden","by","child","classes","."]
code: def _build(self):
      """
      Class-specific build method to be overridden by child classes.
      """
      self.sentinel_tokens = (
          self.src_tokenizer.additional_special_tokens_ids
      )
      assert len(self.sentinel_tokens) > 0
  
imports: from typing import Dict, List
  import numpy
  from nemo.collections.common.tokenizers.tokenizer_spec import TokenizerSpec
  from nemo.collections.nlp.data.common.sequence_to_sequence_dataset import BinarizedMemmapSequenceToSequenceDataset, TextMemmapSequenceToSequenceDataset
  from nemo.collections.nlp.data.language_modeling.megatron.bert_dataset import build_training_sample
  from nemo.collections.nlp.data.language_modeling.megatron.length_distribution_type import LengthDistribution
  from nemo.collections.nlp.data.language_modeling.megatron.t5_dataset import T5Dataset
  from nemo.collections.nlp.data.language_modeling.megatron.ul2_dataset import UL2Dataset
label_desc: Use image node_id 2 for calling the CrossLingualMakedSequenceToSequenceDataset obj's underlying member method code with example usage: obj._build() without return types